P76. Neuralgia following posterior lumbar interbody fusion
1
Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S 146S PURPOSE: To compare the lower thoracic and upper lumbar pedicle widths using MRI, as a measure of the safety and ability to place pedicle screws at these levels. STUDY DESIGN/SETTING: A retrospective study of 118 non-deformity patients, comparing the pedicle isthmic width of the lower thoracic spine (T10-12) and the upper lumbar spine (L1-2) using magnetic resonance imaging. PATIENT SAMPLE: A total of 118 patients (1180 pedicles) were included in the study. Patients ranged in age from 12 to 94, six were less than 18 years of age. There were 58 women and 60 men. OUTCOME MEASURES: All patients were referred for magnetic reso- nance imagines (MRI) study for diagnostic purposes due to either degenera- tive lumbar disease or low back pain. All patients with spinal deformities, pedicle or vertebral fractures, tumors, infections or instrumentation at these levels, were excluded. METHODS: The MRI was obtained using a 1.5-tesla Magnetom Vision unit (Siemens) under a consistent protocol and included the pedicles from T10 through L2 on both sides. The pedicle isthmic width was defined and measured in the axial plane at the narrowest part of the pedicle, perpendicu- lar to the pedicle axis. Difference among levels was assessed with a one- way analysis of variance with post-hoc least significant difference (LSD) to assess pairwise differences. Student’s t test was used to test for difference between genders. Differences in pedicle width due to age and body size were assessed using regression analysis. RESULTS: The pedicle size of T12 was larger than the lumbar pedicles in a vast majority, 99% when compared with L1 and 97% when compared with L2. In 83% of the patients, T10 was larger than the L1. On average, the smallest mean pedicle isthmic width was noted in L1 (mean7.0 mm) and L2 (mean7.2 mm) (no statistical difference). The upper lumbar pedicles were smaller than T12 (mean10.1 mm), T11(mean9.7 mm) and T10 (mean8.5) (post-hoc least significant difference pairwise analysis, p values0.05) (Table 1). No pedicles less than or equal to 5 mm width were observed in the lower thoracic area. Overall, 21 of 118 patients (18%) had at least one pedicle 5 mm in the upper lumbar area, most often at the L1 pedicle. Pedicle widths were larger in males compared with females (p.05). Body size (height and BMI) did not affect the pedicle size. Left pedicles were larger than right pedicles in approximately three-quarters of the vertebra. Table 1 Mean pedicle diameter by level 95% Confidence 95% Confidence Mean Std. deviation interval interval T10 8.5 1.6 5.4 11.5 T11 9.7 1.7 6.4 13.1 T12 10.1 1.5 7.1 13.1 L1 7.0 1.6 3.9 10.1 L2 7.2 1.6 4.1 10.2 CONCLUSIONS: In the 99% of non-deformity patients, the isthmic pedi- cle width of T12 was larger than the upper lumbar pedicles. While none of the lower thoracic isthmic pedicle widths were less than 5 mm, 18% of patients had at least one upper lumbar pedicle with width 5 mm. When planning surgery in the thoracic spine for a given patient, in the vast majority of non-deformity cases, the lower thoracic pedicles will be able to accept larger screws than will the upper lumbar pedicles. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.290 P76. Neuralgia following posterior lumbar interbody fusion Chandra Bhatia, MD, Manoj Krishna, MD, Raymond Pollock, PhD; University Hospital of North Tees, Stockton on Tees, Cleveland, United Kingdom BACKGROUND CONTEXT: Over the last 60 years posterior lumbar interbody fusion (PLIF) has evolved and available instrumentation and implants have improved. However a fear of neurological complications remains. PURPOSE: To study the incidence, aetiology and management of neuralgia following PLIF surgery. By studying this problem, it may be possible to determine the causes of neuralgia and therefore prevent the problem occurring. STUDY DESIGN/SETTING: Prospective case series consisting of pa- tients who underwent PLIF surgery at a spinal unit in a university hospital in the United Kingdom. PATIENT SAMPLE: Two hundred and twenty five patients who met the inclusion criteria for PLIF surgery. This included chronic back pain with degenerative disc disease, grade I–III spondylolisthesis, postlaminectomy syndrome and a large central disc prolapse with back and leg pain. OUTCOME MEASURES: Neuralgia was assessed by patient’s subjective description of their leg pain post PLIF. METHODS: Neuralgia was assessed by patient’s subjective description of their leg pain post PLIF. For type I (see results) neuralgia patients were investigated with CT/MRI and possible reexploration of the nerve roots. Type II were treated with Prednisolone and Gabapentin. If symptoms per- sisted, a nerve root block was performed and possibly reexploration. RESULTS: Sixteen (7%) of the 225 patients who underwent PLIF surgery developed neuralgia. The causes were relative swelling/stenosis (9 patients), screw misplacement (2 patients), conjoined nerve root (2 patients), loose posterior arch (2 patients) and graft subsidence (1 patient). Neuralgia resolved in 11 of the 16 patients. From these results a classification of post PLIF neuralgia is proposed. Type I has its onset 24 hours post surgery and is due to misplaced screw, loose spinous process, conjoined nerve root or bony fragments near the nerve root. Type II has onset 24 hours post surgery and is due to nerve root swelling/relative stenosis or graft subsidence. CONCLUSIONS: The incidence of post PLIF neuralgia can be minimized by performing adequate decompression, peforming total facetectomy, by careful nerve handling and diathermy, avoiding fracture of the spinous process and ensuring removal of bony fragments. If neuralgia does occur aggresive management is essential. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.291 P77. Dynamic stabilization with a flexible pedicle screw system: a preliminary outcomes report with 1-year follow-up from two surgical centers Reginald Davis, MD 1 , James H. Maxwell, MD 2 ; 1 Greater Baltimore Medical Center, Baltimore, MD, USA; 2 Scottsdale Spine Care, Scottsdate, AZ, USA BACKGROUND CONTEXT: Spinal fusion has been the standard treat- ment for radicular pathology secondary to low grade instability and stenotic lesions. In theory, procedures that address the pathology but do not require fusion of the affected segments may be preferable. The Dynesys Spinal System is designed to dynamically stabilize the spine by constraining motion, without reliance on a subsequent solid fusion. Although, there have been in excess of 14,000 implants performed outside the US, there is little published information. PURPOSE: To critically measure clinical outcomes following implantation of the Dynesys Spinal System. STUDY DESIGN/SETTING: This is a prospective outcome report from two centers participating in a multicenter US IDE. PATIENT SAMPLE: The 45 patient cohort consisted of 23 males and 22 females with a mean age of 54.6 yrs. Patients exhibited radicular pathol- ogy for a mean of 6.4 yrs due to instability or stenosing lesions at 1 or 2 contiguous lumbar levels. Seven of the cohort had compensation claims and 11 reported using tobacco products.
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Transcript of P76. Neuralgia following posterior lumbar interbody fusion
Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S146S
PURPOSE: To compare the lower thoracic and upper lumbar pediclewidths using MRI, as a measure of the safety and ability to place pedicle screwsat these levels.STUDY DESIGN/SETTING: A retrospective study of 118 non-deformitypatients, comparing the pedicle isthmic width of the lower thoracic spine(T10-12) and the upper lumbar spine (L1-2) using magnetic resonanceimaging.PATIENT SAMPLE: A total of 118 patients (1180 pedicles) were includedin the study. Patients ranged in age from 12 to 94, six were less than 18years of age. There were 58 women and 60 men.OUTCOME MEASURES: All patients were referred for magnetic reso-nance imagines (MRI) study for diagnostic purposes due to either degenera-tive lumbar disease or low back pain. All patients with spinal deformities,pedicle or vertebral fractures, tumors, infections or instrumentation at theselevels, were excluded.METHODS: The MRI was obtained using a 1.5-tesla Magnetom Visionunit (Siemens) under a consistent protocol and included the pedicles fromT10 through L2 on both sides. The pedicle isthmic width was defined andmeasured in the axial plane at the narrowest part of the pedicle, perpendicu-lar to the pedicle axis. Difference among levels was assessed with a one-way analysis of variance with post-hoc least significant difference (LSD)to assess pairwise differences. Student’s t test was used to test for differencebetween genders. Differences in pedicle width due to age and bodysize were assessed using regression analysis.RESULTS: The pedicle size of T12 was larger than the lumbar pediclesin a vast majority, 99% when compared with L1 and 97% when comparedwith L2. In 83% of the patients, T10 was larger than the L1. On average,the smallest mean pedicle isthmic width was noted in L1 (mean�7.0mm) and L2 (mean�7.2 mm) (no statistical difference). The upper lumbarpedicles were smaller than T12 (mean�10.1 mm), T11(mean�9.7 mm)and T10 (mean�8.5) (post-hoc least significant difference pairwise analysis,p values�0.05) (Table 1). No pedicles less than or equal to 5 mm widthwere observed in the lower thoracic area. Overall, 21 of 118 patients (18%)had at least one pedicle �5 mm in the upper lumbar area, most often atthe L1 pedicle. Pedicle widths were larger in males compared with females(p�.05). Body size (height and BMI) did not affect the pedicle size. Leftpedicles were larger than right pedicles in approximately three-quarters ofthe vertebra.
Table 1Mean pedicle diameter by level
95% Confidence 95% ConfidenceMean Std. deviation interval interval
T10 8.5 1.6 5.4 11.5T11 9.7 1.7 6.4 13.1T12 10.1 1.5 7.1 13.1L1 7.0 1.6 3.9 10.1L2 7.2 1.6 4.1 10.2
CONCLUSIONS: In the 99% of non-deformity patients, the isthmic pedi-cle width of T12 was larger than the upper lumbar pedicles. While noneof the lower thoracic isthmic pedicle widths were less than 5 mm, 18% ofpatients had at least one upper lumbar pedicle with width �5 mm. Whenplanning surgery in the thoracic spine for a given patient, in the vastmajority of non-deformity cases, the lower thoracic pedicles will be ableto accept larger screws than will the upper lumbar pedicles.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.
doi: 10.1016/j.spinee.2005.05.290
P77. Dynamic stabilization with a flexible pedicle screw system: apreliminary outcomes report with 1-year follow-up from twosurgical centersReginald Davis, MD1, James H. Maxwell, MD2; 1Greater BaltimoreMedical Center, Baltimore, MD, USA; 2Scottsdale Spine Care,Scottsdate, AZ, USA
BACKGROUND CONTEXT: Spinal fusion has been the standard treat-ment for radicular pathology secondary to low grade instability and stenoticlesions. In theory, procedures that address the pathology but do not requirefusion of the affected segments may be preferable. The Dynesys SpinalSystem is designed to dynamically stabilize the spine by constrainingmotion, without reliance on a subsequent solid fusion. Although, there havebeen in excess of 14,000 implants performed outside the US, there islittle published information.PURPOSE: To critically measure clinical outcomes following implantationof the Dynesys Spinal System.STUDY DESIGN/SETTING: This is a prospective outcome report fromtwo centers participating in a multicenter US IDE.PATIENT SAMPLE: The 45 patient cohort consisted of 23 males and22 females with a mean age of 54.6 yrs. Patients exhibited radicular pathol-ogy for a mean of 6.4 yrs due to instability or stenosing lesions at 1 or 2contiguous lumbar levels. Seven of the cohort had compensation claimsand 11 reported using tobacco products.
P76. Neuralgia following posterior lumbar interbody fusionChandra Bhatia, MD, Manoj Krishna, MD, Raymond Pollock, PhD;University Hospital of North Tees, Stockton on Tees, Cleveland, UnitedKingdom
BACKGROUND CONTEXT: Over the last 60 years posterior lumbarinterbody fusion (PLIF) has evolved and available instrumentation andimplants have improved. However a fear of neurological complicationsremains.PURPOSE: To study the incidence, aetiology and management of neuralgiafollowing PLIF surgery. By studying this problem, it may be possible todetermine the causes of neuralgia and therefore prevent the problemoccurring.STUDY DESIGN/SETTING: Prospective case series consisting of pa-tients who underwent PLIF surgery at a spinal unit in a university hospitalin the United Kingdom.PATIENT SAMPLE: Two hundred and twenty five patients who met theinclusion criteria for PLIF surgery. This included chronic back pain withdegenerative disc disease, grade I–III spondylolisthesis, postlaminectomysyndrome and a large central disc prolapse with back and leg pain.OUTCOME MEASURES: Neuralgia was assessed by patient’s subjectivedescription of their leg pain post PLIF.METHODS: Neuralgia was assessed by patient’s subjective descriptionof their leg pain post PLIF. For type I (see results) neuralgia patients wereinvestigated with CT/MRI and possible reexploration of the nerve roots.Type II were treated with Prednisolone and Gabapentin. If symptoms per-sisted, a nerve root block was performed and possibly reexploration.RESULTS: Sixteen (7%) of the 225 patients who underwent PLIF surgerydeveloped neuralgia. The causes were relative swelling/stenosis (9 patients),screw misplacement (2 patients), conjoined nerve root (2 patients), looseposterior arch (2 patients) and graft subsidence (1 patient). Neuralgiaresolved in 11 of the 16 patients. From these results a classification of postPLIF neuralgia is proposed. Type I has its onset �24 hours post surgeryand is due to misplaced screw, loose spinous process, conjoined nerve rootor bony fragments near the nerve root. Type II has onset �24 hourspost surgery and is due to nerve root swelling/relative stenosis or graftsubsidence.CONCLUSIONS: The incidence of post PLIF neuralgia can be minimizedby performing adequate decompression, peforming total facetectomy, bycareful nerve handling and diathermy, avoiding fracture of the spinousprocess and ensuring removal of bony fragments. If neuralgia does occuraggresive management is essential.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.
doi: 10.1016/j.spinee.2005.05.291
