Sacral pedicle subtraction osteotomy for an extreme case of positive sagittal balance: case report

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  • 1 Departments of Neurosurgery and
  • 2 Orthopedic Surgery, University of Pennsylvania Health System, Pennsylvania Hospital, Philadelphia, Pennsylvania
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The importance of sagittal spinal balance and lumbopelvic parameters is now well understood. The popularization of various osteotomies, including Smith-Peterson, Ponte, and pedicle subtraction osteotomies (PSOs), as well as vertebral column resections, have greatly enhanced the spine surgeon’s ability to recognize and effectively treat sagittal imbalance. Yet rare circumstances remain, most notably in distal kyphotic deformities and patients with extremely elevated pelvic incidences, where these techniques remain inadequate. In this article, the authors describe a patient with severe sagittal imbalance despite multiple prior anterior and posterior reconstructive surgeries in which a sacral PSO was performed with good results. A description of this technique as well as a brief review of the literature is provided.

ABBREVIATIONS LBP = low-back pain; LL = lumbar lordosis; PI = pelvic incidence; PSO = pedicle subtraction osteotomy; SPO = Smith-Peterson osteotomy; VCR = vertebral column resection.

The importance of sagittal spinal balance and lumbopelvic parameters is now well understood. The popularization of various osteotomies, including Smith-Peterson, Ponte, and pedicle subtraction osteotomies (PSOs), as well as vertebral column resections, have greatly enhanced the spine surgeon’s ability to recognize and effectively treat sagittal imbalance. Yet rare circumstances remain, most notably in distal kyphotic deformities and patients with extremely elevated pelvic incidences, where these techniques remain inadequate. In this article, the authors describe a patient with severe sagittal imbalance despite multiple prior anterior and posterior reconstructive surgeries in which a sacral PSO was performed with good results. A description of this technique as well as a brief review of the literature is provided.

ABBREVIATIONS LBP = low-back pain; LL = lumbar lordosis; PI = pelvic incidence; PSO = pedicle subtraction osteotomy; SPO = Smith-Peterson osteotomy; VCR = vertebral column resection.

Adult spinal deformity is noted with increasing frequency, with studies suggesting a prevalence of approximately 60% in the elderly population.18 While many such cases are benign radiographic findings and do not merit aggressive surgical treatment, the loss of overall spinal balance can also lead to severe pain and disability, prompting the need for intervention. The importance of sagittal balance and spinopelvic parameters is now understood, and the negative effects of positive sagittal balance and lumbar lordosis (LL)–pelvic incidence (PI) mismatch on patient quality of life has been well described in the literature.1,3,7,11,13–15 This common pathology leads to the anterior displacement of the C-7 plumb line with a resultant unbalanced spine, increased use of the lower back musculature, and retroversion of the pelvis. Along with other compensatory mechanisms, this leads to severe low-back pain (LBP) and poor quality of life for patients with this condition.9

Improvements in the understanding of these parameters and surgical techniques to correct underlying causes have made a positive impact on the surgical care of LBP. Most surgical approaches use anterior column lengthening with the use of grafts and lordotic cages, along with posterior column shortening via osteotomies to increase LL. The use of Smith-Peterson (SPO) and Ponte osteotomies, or more extreme lumbar pedicle subtraction osteotomies (PSOs) or vertebral column resections (VCRs), have now enabled the surgeon to obtain excellent improvements in LL, closely matching it to the patient’s PI and correcting the positive sagittal imbalance with relatively predictable improvements in LBP levels and posture.4–6,8,12,16,17

While these techniques are successfully used for clinical and radiographic improvement, shortcomings may occur in situations of sagittal imbalance in the setting of lumbar hyperlordosis, or an extremely elevated PI.2,10 In this paper we report the case of a woman with severe positive sagittal imbalance despite prior anterior and posterior reconstructive surgery with lordotic cages and lumbar PSO who underwent a sacral (S-1) PSO with excellent improvement in her overall alignment and quality of life. We also provide a description of the technique and review of the literature.

Case Report

History and Examination

The patient was a 61-year-old woman with a history of multiple prior spine surgeries for progressive lumbar spondylolisthesis. She first presented for neurosurgical evaluation in 2010 with intractable back pain and proximal leg pain and underwent L3–5 laminectomy and posterior lumbar fusion with L4–5 interbody cage placement. Ten months after surgery, she developed worsening sciatic pain in the right lower extremity. At that time she underwent epidural steroid injections without relief and a second surgery for extension of her fusion from L-3 to S-1 with placement of an L5–S1 interbody cage.

Although her pain initially improved, she presented a year later with worsening back pain as well as bilateral hip and buttock pain. She complained of intermittent pain in both calves as well as foot numbness. At that time, imaging demonstrated anterior subluxation at L4–5 and L5–S1 (Fig. 1A). Standing scoliosis films demonstrated worsening sagittal imbalance (Fig. 2A). She was offered a PSO and declined intervention at the authors’ institution. The patient subsequently underwent an L-4 PSO as well as an L1–2 and L2–3 anterior instrumented fusion and extension of fusion from L-1 to the sacrum at an outside hospital (Fig. 1B). Standing scoliosis films demonstrated progressive sagittal imbalance (Fig. 2B). She returned 3 years later with ongoing LBP (Fig. 2C). She underwent S-1 PSO, resection of the inferior endplate of L-5, and revision of her hardware (Figs. 1C and 2D).

Fig. 1.
Fig. 1.

Sagittal CT reconstruction of the lumbar spine. A: L3–S1 fusion with evidence of prior L4–5 and L5–S1 interbody fusion and flat-back deformity. Myelography dye is seen within the spinal canal. Dashed lines indicate the extent of resection of the sacral PSO. B: L-1 to iliac fusion with evidence of L-4 spondylolisthesis and L-4 PSO. L1–2 and L2–3 interbody cages are present. C: L-1 to iliac fusion with sacral PSO.

Fig. 2.
Fig. 2.

Standing sagittal radiographs demonstrating progression of deformity and resulting correction. A: Anterior subluxation at L4–5 and L5–S1 is noted with severe sagittal imbalance. B: Standing radiograph demonstrating postoperative changes following L-4 PSO and L1–2 and L2–3 anterior instrumented fusion as well as extension of fusion from L-1 to the sacrum. C: The patient had persistent LBP and progression of sagittal imbalance. D: Postoperative radiograph demonstrating S-1 PSO, resection of the inferior endplate of L-5, and revision of posterior segmental instrumentation.

Operative Technique

The patient was placed prone on a Jackson table. An incision was made, extending from L-1 down the sacrum and bilateral iliac wings. The rods were removed and the fusion mass surrounding the prior PSO site was inspected and noted to be grossly stable. The screws at L-1 and L-2 were replaced with larger screws. Four-point iliac fixation was then achieved (Fig. 3). We performed laminectomies extending from L-5 (previously decompressed) down the level of S-3 carrying the decompression laterally such that the bilateral L-5, S-1, and S-2 nerves were clearly visualized. We then began the osteotomy of the sacrum. The plane anterior to the sacral ala was bluntly dissected, and a sponge was placed in this space protecting the iliac vessels. An ultrasonic bone cutter was then used to make osteotomies extending from the dorsal S-1 foramen to the top of the sacral ala including the anterior cortex of the sacrum (Fig. 4). Both S-1 pedicles were then identified and drilled along with the posterior two-thirds of the S-1 vertebral body. In addition, the prior L5–S1 interbody fusion was encountered and resected up to and including portions of the inferior endplate of L-5. The posterior cortex underlying the dura was then fractured after the application of temporary rods connecting the iliac and L-5 screws. The permanent rod was then secured onto the iliac screws and left proud above the lumbar screws. This rod was then pushed down into the lumbar screws to close the PSO with excellent resulting correction of the deformity. Arthrodesis was then performed using autograft as well as human bone morphogenic protein–2 from L-1 to the sacrum using a 4-rod construct and application of a cross connector to restore the integrity of the pelvic ring (Fig. 3).

Fig. 3.
Fig. 3.

Anteroposterior radiograph demonstrating final spinopelvic instrumentation with a 4-rod construct.

Fig. 4.
Fig. 4.

Sacral PSO. The black lines indicate the extent of bone removed to achieve correction. An ultrasonic bone cutter was used to make osteotomies extending from the dorsal S-1 foramen to the top of the sacral ala including the anterior cortex of the sacrum. Figure is available in color online only.

Postoperative Course

Postoperatively, the patient remained neurologically intact with good bowel and bladder function. She remained in the intensive care unit for 2 days, and mobilized with physical therapy on postoperative day 3. She was discharged to a rehabilitation facility on postoperative day 5. She was examined in the clinic 3 months after her surgery and reported significantly improved posture, ability to ambulate, and improved levels of LBP. Standing radiographs obtained revealed a much-improved sagittal balance. The patient’s pre- and postoperative parameters are listed in Table 1.

TABLE 1.

Pre- and postoperative spinopelvic parameters

ParameterPreop (°)Postop (°)
LL5070
PI9580
PI-LL mismatch4510
Sagittal vertical axis16.57.5
Pelvic tilt2825
Sacral slope6057

Discussion

The use of anterior column lengthening via cages or grafts and/or posterior column shortening via SPOs, PSOs, or VCRs of the mobile lumbar spine are highly effective in treating sagittal imbalance in situations in which LL has been lost, and this is noted in the large majority of cases. The use of lumbar subtraction osteotomies to achieve this is commonplace, and the techniques are well described in the literature. However, these methods have limited utility when the loss of lordosis occurs more distally at the lumbosacral junction with a compensatory hyperlordosis of the lumbar spine, as can been seen with high-grade spondylolisthesis/spondyloptosis at L5–S1, or in patients with extremely elevated PI. Under these circumstances, increasing the LL to match the PI may be irrational and technically unfeasible.

Sacral subtraction osteotomies are infrequently used but ideal for such circumstances. First described by Hsieh et al.,10 the use of bilateral alar osteotomies enables the surgeon to change the PI and reorient the pelvis in relation to the sacrum. In addition, anterior pelvic additions in the form of bilateral Salter osteotomies have also been described and have been found to be effective.2

We presented the case of a patient who had severe lumbosacral kyphosis, who had undergone L1–2 and L2–3 lateral interbody instrumentation in addition to an L-4 PSO. Despite this, she remained unable to maintain erect posture and had severe LBP. Reduction of her PI via S-1 PSO was, in our opinion, her best option and we were able to achieve a successful outcome utilizing this technique. This technique typically has the added benefit of avoiding a massive postsurgical scar because many times laminectomies end at the level of L5–S1. Because we also removed the inferior portion of L-5, our surgery resulted in an increase in the patient’s LL as well as a decrease in her PI, helping significantly with her PI-LL mismatch as well as her positive sagittal vertical axis. While necessary in rare circumstances and technically challenging, this method is nevertheless effective and feasible to treat this difficult group of patients.

We acknowledge the limitations of this report. While the patient’s radiographic outcome is encouraging, it is important to note that she will be followed in clinic for years to determine the durability of her sacral PSO and the correction of her sagittal imbalance. Long-term follow-up and greater patient sample sizes are needed to understand the true utility of this technique.

In conclusion, in extreme cases of kyphosis at the lumbosacral junction with satisfactory lordosis or hyperlordosis of the lumbar spine, sacral PSO at S-1 is a safe and effective method to restore LL-PI equilibrium.

Disclosures

The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

Author Contributions

Conception and design: Ozturk. Acquisition of data: Ozturk. Analysis and interpretation of data: Sullivan. Drafting the article: Sullivan. Critically revising the article: Arlet. Reviewed submitted version of manuscript: Arlet.

References

  • 1

    Barrey C, Jund J, Noseda O, Roussouly P: Sagittal balance of the pelvis-spine complex and lumbar degenerative diseases. A comparative study about 85 cases. Eur Spine J 16:14591467, 2007

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2

    Bodin A, Roussouly P: Sacral and pelvic osteotomies for correction of spinal deformities. Eur Spine J 24 (Suppl 1):S72S82, 2015

  • 3

    Boulay C, Tardieu C, Hecquet J, Benaim C, Mouilleseaux B, Marty C, : Sagittal alignment of spine and pelvis regulated by pelvic incidence: standard values and prediction of lordosis. Eur Spine J 15:415422, 2006

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Bridwell KH: Decision making regarding Smith-Petersen vs. pedicle subtraction osteotomy vs. vertebral column resection for spinal deformity. Spine (Phila Pa 1976) 31 (19 Suppl):S171S178, 2006

    • Search Google Scholar
    • Export Citation
  • 5

    Bridwell KH, Lenke LG, Lewis SJ: Treatment of spinal stenosis and fixed sagittal imbalance. Clin Orthop Relat Res (384):3544, 2001

  • 6

    Chang KW, Cheng CW, Chen HC, Chang KI, Chen TC: Closing-opening wedge osteotomy for the treatment of sagittal imbalance. Spine (Phila Pa 1976) 33:14701477, 2008

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Gangnet N, Dumas R, Pomero V, Mitulescu A, Skalli W, Vital JM: Three-dimensional spinal and pelvic alignment in an asymptomatic population. Spine (Phila Pa 1976) 31:E507E512, 2006

    • Search Google Scholar
    • Export Citation
  • 8

    Gill JB, Levin A, Burd T, Longley M: Corrective osteotomies in spine surgery. J Bone Joint Surg Am 90:25092520, 2008

  • 9

    Glassman SD, Bridwell K, Dimar JR, Horton W, Berven S, Schwab F: The impact of positive sagittal balance in adult spinal deformity. Spine (Phila Pa 1976) 30:20242029, 2005

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Hsieh PC, Ondra SL, Wienecke RJ, O’Shaughnessy BA, Koski TR: A novel approach to sagittal balance restoration following iatrogenic sacral fracture and resulting sacral kyphotic deformity. Technical note. J Neurosurg Spine 6:368372, 2007

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Jackson RP, Peterson MD, McManus AC, Hales C: Compensatory spinopelvic balance over the hip axis and better reliability in measuring lordosis to the pelvic radius on standing lateral radiographs of adult volunteers and patients. Spine (Phila Pa 1976) 23:17501767, 1998

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Kelly DG, Kerlin P, Sarr MG, Phillips SF: Ricinoleic acid causes secretion in autotransplanted (extrinsically denervated) canine jejunum. Dig Dis Sci 26:966970, 1981

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Kuntz C IV, Levin LS, Ondra SL, Shaffrey CI, Morgan CJ: Neutral upright sagittal spinal alignment from the occiput to the pelvis in asymptomatic adults: a review and resynthesis of the literature. J Neurosurg Spine 6:104112, 2007

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Lafage V, Schwab F, Skalli W, Hawkinson N, Gagey PM, Ondra S, : Standing balance and sagittal plane spinal deformity: analysis of spinopelvic and gravity line parameters. Spine (Phila Pa 1976) 33:15721578, 2008

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Lee CS, Lee CK, Kim YT, Hong YM, Yoo JH: Dynamic sagittal imbalance of the spine in degenerative flat back: significance of pelvic tilt in surgical treatment. Spine (Phila Pa 1976) 26:20292035, 2001

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Mummaneni PV, Dhall SS, Ondra SL, Mummaneni VP, Berven S: Pedicle subtraction osteotomy. Neurosurgery 63 (3 Suppl):171176, 2008

  • 17

    Rose PS, Bridwell KH, Lenke LG, Cronen GA, Mulconrey DS, Buchowski JM, : Role of pelvic incidence, thoracic kyphosis, and patient factors on sagittal plane correction following pedicle subtraction osteotomy. Spine (Phila Pa 1976) 34:785791, 2009

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Schwab F, Dubey A, Gamez L, El Fegoun AB, Hwang K, Pagala M, : Adult scoliosis: prevalence, SF-36, and nutritional parameters in an elderly volunteer population. Spine (Phila Pa 1976) 30:10821085, 2005

    • Crossref
    • Search Google Scholar
    • Export Citation

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Contributor Notes

Correspondence Ali Kemal Ozturk: University of Pennsylvania Health System, Philadelphia, PA. ali.ozturk@uphs.upenn.edu.

INCLUDE WHEN CITING Published online February 9, 2018; DOI: 10.3171/2017.8.SPINE17550.

Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

  • View in gallery

    Sagittal CT reconstruction of the lumbar spine. A: L3–S1 fusion with evidence of prior L4–5 and L5–S1 interbody fusion and flat-back deformity. Myelography dye is seen within the spinal canal. Dashed lines indicate the extent of resection of the sacral PSO. B: L-1 to iliac fusion with evidence of L-4 spondylolisthesis and L-4 PSO. L1–2 and L2–3 interbody cages are present. C: L-1 to iliac fusion with sacral PSO.

  • View in gallery

    Standing sagittal radiographs demonstrating progression of deformity and resulting correction. A: Anterior subluxation at L4–5 and L5–S1 is noted with severe sagittal imbalance. B: Standing radiograph demonstrating postoperative changes following L-4 PSO and L1–2 and L2–3 anterior instrumented fusion as well as extension of fusion from L-1 to the sacrum. C: The patient had persistent LBP and progression of sagittal imbalance. D: Postoperative radiograph demonstrating S-1 PSO, resection of the inferior endplate of L-5, and revision of posterior segmental instrumentation.

  • View in gallery

    Anteroposterior radiograph demonstrating final spinopelvic instrumentation with a 4-rod construct.

  • View in gallery

    Sacral PSO. The black lines indicate the extent of bone removed to achieve correction. An ultrasonic bone cutter was used to make osteotomies extending from the dorsal S-1 foramen to the top of the sacral ala including the anterior cortex of the sacrum. Figure is available in color online only.

  • 1

    Barrey C, Jund J, Noseda O, Roussouly P: Sagittal balance of the pelvis-spine complex and lumbar degenerative diseases. A comparative study about 85 cases. Eur Spine J 16:14591467, 2007

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 2

    Bodin A, Roussouly P: Sacral and pelvic osteotomies for correction of spinal deformities. Eur Spine J 24 (Suppl 1):S72S82, 2015

  • 3

    Boulay C, Tardieu C, Hecquet J, Benaim C, Mouilleseaux B, Marty C, : Sagittal alignment of spine and pelvis regulated by pelvic incidence: standard values and prediction of lordosis. Eur Spine J 15:415422, 2006

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Bridwell KH: Decision making regarding Smith-Petersen vs. pedicle subtraction osteotomy vs. vertebral column resection for spinal deformity. Spine (Phila Pa 1976) 31 (19 Suppl):S171S178, 2006

    • Search Google Scholar
    • Export Citation
  • 5

    Bridwell KH, Lenke LG, Lewis SJ: Treatment of spinal stenosis and fixed sagittal imbalance. Clin Orthop Relat Res (384):3544, 2001

  • 6

    Chang KW, Cheng CW, Chen HC, Chang KI, Chen TC: Closing-opening wedge osteotomy for the treatment of sagittal imbalance. Spine (Phila Pa 1976) 33:14701477, 2008

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Gangnet N, Dumas R, Pomero V, Mitulescu A, Skalli W, Vital JM: Three-dimensional spinal and pelvic alignment in an asymptomatic population. Spine (Phila Pa 1976) 31:E507E512, 2006

    • Search Google Scholar
    • Export Citation
  • 8

    Gill JB, Levin A, Burd T, Longley M: Corrective osteotomies in spine surgery. J Bone Joint Surg Am 90:25092520, 2008

  • 9

    Glassman SD, Bridwell K, Dimar JR, Horton W, Berven S, Schwab F: The impact of positive sagittal balance in adult spinal deformity. Spine (Phila Pa 1976) 30:20242029, 2005

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Hsieh PC, Ondra SL, Wienecke RJ, O’Shaughnessy BA, Koski TR: A novel approach to sagittal balance restoration following iatrogenic sacral fracture and resulting sacral kyphotic deformity. Technical note. J Neurosurg Spine 6:368372, 2007

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Jackson RP, Peterson MD, McManus AC, Hales C: Compensatory spinopelvic balance over the hip axis and better reliability in measuring lordosis to the pelvic radius on standing lateral radiographs of adult volunteers and patients. Spine (Phila Pa 1976) 23:17501767, 1998

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Kelly DG, Kerlin P, Sarr MG, Phillips SF: Ricinoleic acid causes secretion in autotransplanted (extrinsically denervated) canine jejunum. Dig Dis Sci 26:966970, 1981

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Kuntz C IV, Levin LS, Ondra SL, Shaffrey CI, Morgan CJ: Neutral upright sagittal spinal alignment from the occiput to the pelvis in asymptomatic adults: a review and resynthesis of the literature. J Neurosurg Spine 6:104112, 2007

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Lafage V, Schwab F, Skalli W, Hawkinson N, Gagey PM, Ondra S, : Standing balance and sagittal plane spinal deformity: analysis of spinopelvic and gravity line parameters. Spine (Phila Pa 1976) 33:15721578, 2008

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Lee CS, Lee CK, Kim YT, Hong YM, Yoo JH: Dynamic sagittal imbalance of the spine in degenerative flat back: significance of pelvic tilt in surgical treatment. Spine (Phila Pa 1976) 26:20292035, 2001

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Mummaneni PV, Dhall SS, Ondra SL, Mummaneni VP, Berven S: Pedicle subtraction osteotomy. Neurosurgery 63 (3 Suppl):171176, 2008

  • 17

    Rose PS, Bridwell KH, Lenke LG, Cronen GA, Mulconrey DS, Buchowski JM, : Role of pelvic incidence, thoracic kyphosis, and patient factors on sagittal plane correction following pedicle subtraction osteotomy. Spine (Phila Pa 1976) 34:785791, 2009

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Schwab F, Dubey A, Gamez L, El Fegoun AB, Hwang K, Pagala M, : Adult scoliosis: prevalence, SF-36, and nutritional parameters in an elderly volunteer population. Spine (Phila Pa 1976) 30:10821085, 2005

    • Crossref
    • Search Google Scholar
    • Export Citation

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