Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Proximal junctional kyphosis after deformity surgery
Introduction
Adult spinal deformity is a prevalent pathology with increasing incidence in the aging population. The correction of this pathology requires multilevel fusion, which unfortunately results in frequent revision. Proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) are common and serious complications following long constructs for spinal deformity. It has been reported to occur in up to 39% of adult spinal deformity cases. PJK is defined as a sagittal Cobb angle ≥10 degrees and at least 10 degrees greater than the preoperative measurement, while PJF is defined as any type of symptomatic PJK requiring revision surgery. The etiology is thought to be multifactorial. It can result in symptoms of back pain, kyphotic deformity, and even neurological deficit from spinal cord and/or nerve root compression. Because PJK has broad implications for both symptomatic and asymptomatic patients, two separate classification systems have emerged. In 2012, Yati et al. proposed a classification system that allowed description by type (type 1 = ligamentous failure; type 2 = bone failure; type 3 = implant or bone interface failure), severity (grade A, B, or C corresponding to an increase in the PJA of 10 to 14 degrees, 15 to 19 degrees, or >20 degrees, respectively), and the presence (S) or absence (N) of spondylolisthesis ( Table 34.1 ). Laue et al. proposed a PJK severity scale that integrates six components, which are stratified and assigned a point value and summed for total severity score: neurological deficit, focal pain, instrumentation problems, change in kyphosis/posterior ligament complex integrity, fracture location, and level of upper instrumentated vertebrae (UIV) ( Table 34.2 ). Although no known technique exists to prevent PJK, there are factors that may reduce its incidence.
Example case
-
Chief complaint: back pain
-
History of present illness: A 67-year-old female who underwent T10 to pelvis instrumented fusion for scoliosis ( Figs. 34.1 – 34.3 ) repair 7 months prior presents with recurrent back pain. She did well postoperatively with improvement of her back pain, leg pain, and posterior. However, she also presents with increasing worsening upper thoracic back pain and increasing kyphosis. Imaging showed concern for PJK (Fig. 34.4 ). She denies any weakness, numbness, or bowel/bladder dysfunction.
-
Medications: rosuvastatin, paroxetine, carvedilol, ramipril, timolol, trazodone
-
Allergies: no known drug allergies
-
Past medical and surgical history: T10 to pelvis instrumented fusion for scoliosis repair, osteopenia, diabetes, depression, anxiety, hypertension, hyperlipidemia
-
Family history: noncontributory
-
Social history: teacher, no smoking history, occasional alcohol
-
Physical examination: awake, alert, and oriented to person, place, and time; cranial nerves II–XII intact; bilateral deltoids/triceps/biceps 5/5; interossei 5/5; iliopsoas/knee flexion/knee extension/dorsi, and plantar flexion 5/5
-
Reflexes: 2+ in bilateral biceps/triceps/brachioradialis with negative Hoffman; 2+ in bilateral patella/ankle; no clonus or Babinski; sensation intact to light touch
|
|
|
|
|
|---|---|---|---|---|
| Preoperative | ||||
| Additional tests requested |
|
|
|
|
| Surgical approach selected | If pain is disabling, T4 to pelvis fusion with T9-10 and T10-11 posterior column osteotomies | T9-10, T10-11 Smith-Peterson osteotomies and T2-12 posterior fusion | T9-10 posterior column osteotomy, revision instrumentation from T2, T3, or T4 to L2 or L3 | If kyphosis progresses or symptoms are disabling, L4 pedicle subtraction osteotomy and T4-pelvis fusion |
|
|
|
|
|
| Goal of surgery | Restoration of sagittal balance, improve pain | Restoration of sagittal balance, obtain solid fusion, improve pain, enhance mobility | Restoration of sagittal balance, minimize chance of proximal junctional kyphosis, improve pain and postural imbalance | Restoration of sagittal balance, improve pain |
| Perioperative | ||||
| Positioning | Prone on Jackson table | Prone on Allen table, with Mayfield pins | Prone with Gardner-Wells tongs | Prone on Jackson table |
| Surgical equipment |
|
|
|
|
| Medications | Tranexamic acid | Tranexamic acid, MAP >80 | Tranexamic acid, steroids | Tranexamic acid |
| Anatomical considerations | Dura/spinal cord, interspinous ligaments, facet joints at top of construct | Pedicle anatomy, spinal cord, nerve roots, aorta | Posterior column abnormalities, prior laminectomy defects | L4-5 nerve roots, thecal sac, spinal cord |
| Complications feared with approach chosen | Proximal junctional kyphosis in upper thoracic spine, pseudoarthrosis, delayed implant fracture | Spinal cord/nerve root injury, excessive bleeding, pedicle fracture, malposition of implants, posterior ischemic optic neuropathy | CSF leak, excessive upper lumbar/lower thoracic lordosis | Spinal cord/nerve root injury, blood loss/hemodynamic instability |
| Intraoperative | ||||
| Anesthesia | General | General | General | General |
| Exposure | T4-pelvis | T2-L2 | T3-L3 | T4-pelvis |
| Levels decompressed | None | None | T9-10 | L4 |
| Levels fused | T4-pelvis | T2-L2 | T3-L3 | T4-pelvis |
| Surgical narrative | Position prone, expose T4 to pelvis including prior implants, inspect prior fusion, routine soft tissue culture to evaluate for subclinical infection, place pedicle screws from T4-T9, perform T9-T11 posterior column osteotomies, remove set screws down to 2 levels below where domino will be placed, stagger domino placement to avoid stress of two dominoes at same level, use rod bender to bend proximal rod up, remove pedicle screws where dominoes will go, cut rod in situ with rod cutter, place dominoes onto cut ends of rods, bend distal rods back down with new rods placed into dominoes, new rods are bent down into proximal spine to T4, gentle cantilever can be applied to correct kyphosis but ensure proximal rod is kyphotic, set screws are placed, final tighten set screws, decortication of posterior elements across entire exposure, placement of autograft and allograft, layered closure with two subfascial drains | Position prone with Mayfield pins using Allen table sandwich flip, IOM, posterior midline exposure, expose T2-T12, cut rods at T10, evaluate if pedicle screws T10-T12 are solid or loose, replace with bigger screws if loose, clamp reference frame, O-arm spins to cover T2-8 and T8-T12, cannulate pedicles from T2-T9 and likely replace T10 pedicle screws, perform Smith-Peterson osteotomies at T9-10 and T10-11 bilaterally with bur and Kerrison punches, contour rods to desired curvature, decorticate exposed bony surfaces, place rods, use side-to-side connectors to connect new rod to the previous rod at T11 and T12, use manual positioning and gentle compression to reduce kyphosis, final O-arm spine to confirm hardware placement and satisfactory alignment correction, local bone and two units of BMP for fusion, local anesthetic and vancomycin powder, layered closure with subfascial drain | Position prone with Gardner-Wells tongs and avoid hyper lordosis, subperiosteal exposure up to T2, T3, or T4 and minimize tissue disruption and down to prior implants at L2 or L3, place vancomycin powder into muscle and subcutaneous tissue, check fixation from T10 to L3, consider exposing all the way to sacrum/ilium if the hardware is loose or spine not fused, remove inferior facets from T3 to 4 down to T9-10 if T3 chosen as upper level, remove rods from T10 to L3 by cutting short third rod on left side, check screw purchase of remaining screws and replace if not solid, place bilateral pedicle screws up to T3 with freehand technique, posterior column osteotomies at T9-10 and TLIF if unstable or needed for segmental kyphosis correction, O-arm to assess screw and cage placement, reinstrumentation placed from T3 to L2 on left and T3-L3 on right with cantilever and posterior compressive correction of lower thoracic junctional kyphosis and recreate normal kyphosis from T3 to 6, new rods connected to old rods with rod-rod connectors, intraoperative long cassette stitched x-rays to evaluate alignment, fusion with auto/allograft and potentially BMP especially in thoracolumbar junction, layered closure with deep and superficial drain with vancomycin and tobramycin powder into muscle and subcutaneous tissue | Position prone, preferably on Jackson table, incision above the old scar until T4, pedicle instrumentation T4 to T9 with free hand technique, identify previous instrumented area. Remove taps from T10 to L2 or L3, check if it is possible to pull the rod and put it aside. Otherwise, cut the rods below L1 and remove the rod between T10 and L1, remove T12 screw at one side and L1 at the other side, check the purchase of the remaining screws, if any of them is loose or has not a good purchase, change it. Then, perform Smith-Petersen osteotomies T9/T10 and T10/T11. Place hooks at T3, and cut rods and bend them according to previously calculated and desired kyphosis. Place rods, close osteotomies performing local compression, connect rods with more caudal rods with end-to-end connectors. Check fluoroscopy if adequate correction has been obtained. Close the system under slight compression. Add DTT/cross-link at osteotomy site. Add bone graft. Layered wound closure, applying vancomycin at the subcutaneous layer. |
| Complication avoidance | Evaluate for subclinical infection, domino rod placement that is staggered, cantilever rods to correct kyphosis | Surgical navigation, evaluate previous screws for loosening, Smith-Peterson osteotomies for sagittal correction, domino rods to previous rods, BMP | Avoid hyper lordosis during positioning, avoid tissue mobilization at upper surgical level, extend down to sacrum/ilium if previous hardware loose or not fused during intraoperative evaluation, O-arm to assess hardware, different ending points distally to offset implants, rod-rod connectors to make sure stable, intraoperative long cassette stitched x-rays to evaluate alignment | IONM, careful positioning and check fluoroscopy after positioning, take intraoperative cultures to rule out subclinic infection. |
| Postoperative | ||||
| Admission | ICU | Stepdown unit | ICU | ICU |
| Postoperative complications feared | Medical complications, wound infection, proximal junctional kyphosis in upper thoracic spine, pseudoarthrosis, delayed implant fracture | Wound infection, screw pullout, early hardware failure, medical complications | Medical complications, CSF leak, excessive upper lumbar/lower thoracic lordosis | Wound infection, CSF leak, Pseudoarthrosis, rod breakage |
| Anticipated length of stay | 5–7 days | 5–7 days | 4 days | 8–9 days |
| Follow-up testing | Full length standing x-rays prior to discharge, 3 months, 6 months, 1 year, 2 years after surgery |
|
Upright x-rays after drains removed | Full-standing x-rays before discharge |
| Bracing | None | None | None | None |
| Follow-up visits | 2 weeks, 6 weeks, 3 months, 6 months, 1 year, 2 years after surgery | 6 weeks, 3 months, 6 months, 12 months, 24 months after surgery | 2 weeks, 6–8 weeks after surgery | 2 weeks, 6 weeks, 6 months, 1 and 2 years |
CSF , Cerebrospinal fluid; CT , computed tomography; BMP , bone morphogenic protein; DEXA , dual-energy x-ray absorptiometry; EMG , electromyography; ICU , intensive care unit; IOM , intraoperative monitoring; MAP , mean arterial pressure; MEP , motor evoked potential; MRI , magnetic resonance imaging; SSEP , somatosensory evoked potential; TLIF , transforaminal lumbar interbody fusion.
Table 34.1
Modified Boachie-Adjei Classification of Proximal Junctional Kyphosis
| Type | Definition |
|---|---|
| 1 | Ligamentous failure |
| 2 | Bone failure |
| 3 | Implant and bone interface failure |
| Grades | Definition |
| A | Proximal junctional increase 10–19 degrees |
| B | Proximal junctional increase 20–29 degrees |
| C | Proximal junctional increase ≥30 degrees |
| Spondylolisthesis | Definition |
| N | No obvious spondylolisthesis above UIV |
| S | Spondylolisthesis above UIV |
Table 34.2
Hart-International Spine Study Group Proximal Junctional Kyphosis Severity Scale
| Characteristic | Severity Score (points) |
|---|---|
| Neurological Deficit | |
| None | 0 |
| Radicular pain | 2 |
| Myelopathy/motor deficit | 4 |
| Focal pain | |
| None | 0 |
| VAS ≤4 | 1 |
| VAS ≥5 | 3 |
| Instrumentation Problem | |
| None | 0 |
| Partial fixation loss | 1 |
| Prominence | 1 |
| Complete fixation loss | 2 |
| Change in Kyphosis/PLC Integrity | |
| 0–10 degrees | 0 |
| 10–20 degrees | 1 |
| >20 degrees | 2 |
| PLC failure | 2 |
| UIV/UIV + 1 fracture | |
| None | 0 |
| Compression fracture | 1 |
| Burst/chance fracture | 2 |
| Translation | 3 |
| Level of UIV | |
| Thoracolumbar junction | 0 |
| Upper thoracic | 1 |
| VAS, visual analogue scale; PLC, posterios ligamentous complex; UIV, upper instrumented vertebrae | |
Differential diagnosis
- ▪
Proximal junctional kyphosis
- ▪
Proximal junctional failure
- ▪
Adjacent segment disease
You're Reading a Preview
Become a Clinical Tree membership for Full access and enjoy Unlimited articles
If you are a member. Log in here