Oswestry disability index

Originally published by Jeremy Fairbank in 1980, the Oswestry Disability Index (ODI) is a validated functional measurement for evaluating axial LBP. ^, In recent years, it has been extrapolated to measure responsiveness to SIJ pain interventions. The questionnaire produces a score to quantify level of functional disability related to activities of daily living (ADL)s, that is, pain intensity, personal care, lifting, walking, sitting, standing, sleep, sex life, and traveling ( Fig. 9.1 ). Each disability in ADL is scored from 0 to 5, with 0 indicating no pain to 5 indicating the worst pain imaginable. The scores are then added and converted to a percentage of the maximum score of 50. The resulting percentage can be used to measure the level of disability ( Table 9.1 ).

Oswestry Disability Index questionnaire.

(From Costa M, Marshman L. Sex life and the Oswestry Disability Index. Spine J. 2015;15(6):1227.)

The ODI has historically been a functional assessment tool for axial related back pain but has received growing traction for its utility for SIJ related pain in recent years. A 2015 prospective multicenter clinical study, conducted by Copay and Cher attempted to determine the change in ODI that corresponds to the minimum clinically important difference (MCID), the smallest change in pain that is considered important to patients, for patients undergoing SIJ fusion and compare the values with those already established for lumbar surgeries. A total of 155 participants underwent examination to recruit participants who were experiencing exclusively SIJ-related back pain and who underwent minimally invasive SIJ fusion. These participants were assessed at baseline and 1, 3, 6, and 12 months after joint fusion with postsurgical follow-up assessments using the ODI questionnaire, Health Transition Item (HTI) of the Short Form Health Survey (SF-36), and a postsurgical satisfaction scale. HTI compares current health with health 1 year prior. At 6- and 12-month intervals, patients were asked to rate their level of satisfaction with surgery. These three measures were selected as global assessments of change and as proxy for objective measures of change, essentially pivotal anchors to determine the MCID.

The MCID has been well established for the ODI for patients after lumbar surgery, typically ranging from 7% to 15%. MCID is determined by a series of calculations, including the following: (1) determination of the minimum detectable change (MDC) defined as the smallest change that can be considered above measurement error with 95% confidence, <SPAN role=presentation tabIndex=0 id=MathJax-Element-1-Frame class=MathJax style="POSITION: relative" data-mathml='MDC=1.96×2′>MDC=1.96x2‾√MDC=1.96×2
MDC = 1 . 96 x 2
× Standard error of measurement (SEM); (2) the average change of the HTI versus the satisfaction scale; (3) the change difference between the average change scores of the HTI versus the satisfaction scale; and (4) the receiver operating characteristic curve approach, in which MCID is the change score that differentiates within each individual group, respectively. In the Copay and Cher study, the ODI change score was statistically associated with the HTI ( r = 0.49; P <.0001) and the satisfaction scale ( r = 0.34; P <.0001). The estimated MCID for ODI resulted in a range between 13% and 15% in this study. This falls within the range of the previously established MCID for lumbar back pain (7%–15%) indicating that ODI may be a valid measure for SIJ disability and that it is sensitive to change in disability.

Short form health survey questionnaire

The SF-36 is used as an assessment tool to measure a quality of life after surgery. The SF-36 is comprehensive health survey with a total of 36 questions divided into eight categories, including physical functioning (10 items), bodily pain (2 items), role limitations due to physical health problems (4 items), role limitations due to personal or emotional problems (4 items), emotional well-being (5 items), social functioning (2 items), energy/fatigue (4 items), and general health perceptions (5 items). However, the SF-36 is limited by its lack of assessment of sleep quality, which is pertinent when assessing pain interference with ADLs. The score averages for each category range from 0 to 100, with a higher score defining a more favorable outcome. In addition, the SF-36 may include a HTI, which asks participants retrospective questions. For example, they rate their general health compared with 1 year prior, with five categories of choice, “much better,” “somewhat better,” “about the same,” “somewhat worse,” and “much worse.” Overall the SF-36 can be used in conjunction with other assessment tools, such as the ODI, to better evaluate the efficacy of proposed treatments and pain related disability. ^,

Visual analog scale

The visual analog scale (VAS) is an additional scale used to determine pain intensity. It consists of a line, approximately 100 mm in length, illustrated in Figure 9.2 . The left side signifies no pain, and the right side signifies the worst pain imaginable. There are recommended intervals associated with the intensity of pain, which are no pain (0–4 mm), mild pain (5–44 mm), moderate pain (45–74 mm), and severe pain (75–100 mm). The VAS is most beneficial in self-reported pain that ranges across a spectrum of values that cannot easily be directly measured with a singular value.

The visual analog scale.

(From Benzon H, Raja S, Fishman S, Liu S, Cohen S. Essentials of Pain Medicine: Pain Assessment . 3rd ed. Philadelphia: Saunders Elsevier; 2017:29.)

The brief pain inventory

The Brief Pain Inventory (BPI) is a multidimensional pain inventory that can reliably provide a measure of the effect of pain on an individual’s physical and social functioning. The BPI consists of a nine-part questionnaire and is available in a short (15 items) ( Fig. 9.3 ) and a long format (32 items). The questions are meant to gauge the severity of pain levels (worst, least, average, and current), the impact of pain on daily functioning in different areas (mood, walking, relationships, sleep, normal work, and general activity), and current treatments with perceived effectiveness of those treatments. The long form of the BPI includes more in-depth questions, including demographic information (age, marital status, education), pain history, aggravating and easing factors, treatment and medication, pain quality, and response to treatment. ^,

The Brief Pain Inventory (Short Form).

(From Waldman SW. Pain management. In: The Evaluation of the Patient in Pain . 2nd ed. Philadelphia: Saunders; 2011:198.)

Numeric pain rating scale

The Numeric Pain Rating Scale (NPRS) is perhaps the most frequently applied scale used to quantify pain intensity in the clinical setting. It is an 11-point numeric scale, ranging from 0 indicating no pain to 10 indicating worst pain imaginable ( Fig. 9.4 ). Although the NPRS is relatively straightforward and efficient, its utility is limited by its incorporation of only one facet of pain. Because of its simplicity, clinicians may not be able to assess the complexity and idiosyncratic nature of the full pain experience.

The Numeric Pain Rating Scale.

(From Benzon H, Raja S, Fishman S, Liu S, Cohen S. Essentials of Pain Medicine: Pain Assessment . 3rd ed. Philadelphia: Saunders Elsevier; 2017:29.)

Localized steroid injection

Although SIJ injection is an invaluable diagnostic tool, its therapeutic efficacy remains controversial. One retrospective analysis studied 49 patients with pain overlying the posterior superior iliac spine and one or more positive provocative SIJ test results (sacral thrust, Patrick’s test, Gaenslen’s test) who subsequently underwent unilateral, fluoroscopically guided SIJ corticosteroid injection. To measure efficacy of the intervention, NPRS scores were compared at baseline and at 2 and 8 weeks after intervention. The scoring scale ranged from 0 (no pain) to 10 (severe disabling pain), with a successful outcome defined as a greater than 1.7-point decrease. At both 2 and 8 weeks after the procedure, participants demonstrated significant reductions in NPRS scores (6.6 ± 1.9 at baseline; 2.8 ± 1.4 at 2 weeks; 4.0 ± 1.6 at 8 weeks; P <.0001). Given these supportive findings, the authors cited imprecise technique and inaccurate diagnosis of LBP as barriers to widespread application of localized steroid injection.

In another study, 24 patients with chronic SIJ pain (>6-month duration), refractory to conservative medical therapies, were treated with fluoroscopically guided intraarticular injection of 0.5 mL of 2% lidocaine and 10 mg of triamcinolone followed by periarticular injection of 0.3 mL of 2% lidocaine and 5 mg of triamcinolone. Inclusion criteria were at least one positive SIJ pain provocation test result (pressure application to an SI ligament, Gaenslen’s test, Patrick’s test), at least 50% pain relief for more than 30 minutes after diagnostic block with the aforementioned injectate, and baseline pain scores greater than 4 on the NPRS score for pain. Treatment efficacy was measured with the NPRS, the ODI, and global perceived effect (GPE) scores; GPE was evaluated on a seven-point Likert scale with higher scores indicating increased patient satisfaction. Evaluations were completed preprocedurally and at 2 and/or 4 weeks postprocedurally. Successful treatment was defined as 50% reduction from baseline NPRS score. Results demonstrated decreases in mean NPRS scores of all patients from baseline (mean ± standard deviation [SD], 6.4 ± 1.2) to 2 weeks (2.2 ± 1.1) and 4 weeks (2.3 ± 1.1) after treatment ( P <.05). Similarly, there were decreases in ODI scores from baseline (61% ± 15%) to 2 weeks (21% ± 12%) and 4 weeks (23% ± 11%) after treatment ( P <.05). Last, with GPE scores of 6 or greater, 79% of patients reported satisfaction with treatment at 4 weeks. Although this study had a relatively small sample size and was intended to compare the efficacy of an alternative technique, it simultaneously attests to the therapeutic efficacy of corticosteroid injections.

Todorov and Batalov implemented similar measures to compare ultrasound-guided versus landmark-guided SIJ injections. Forty-four patients with spondyloarthritic SIJ pain unresponsive to nonsteroidal antiinflammatory drugs and three or more positive SIJ pain provocative maneuvers (iliac gapping, iliac compression, midline sacral thrust, Gaenslen’s test, Patrick’s test, sulcus test) were randomized to receive ultrasound- or landmark-guided injection of 7 mg betamethasone (1 mL) and 1% lidocaine (1.5 mL). Self-assessments included the VAS (scored from 0 to 10), Roland-Morris Disability Questionnaire (RMDQ; scored from 0 to 24 quantifying functional disability), and Jenkins Sleep Evaluation Questionnaires (JSEQ; scored from 0 to 20 quantifying sleep disturbance). Assessments were completed before intervention and at 8 weeks after intervention. At the 8-week interval, both groups reported improvements in all outcome parameters. The VAS mean score decreased by 68% and 31% in the ultrasound and landmark groups, respectively, with P = .004 representing the significant difference between group responses. RMDQ scores decreased by 46% and 12% in the ultrasound and landmark groups ( P = .031), respectively. Last, JSEQ scores decreased by 41% and 22% in the ultrasound and landmark groups ( P = .036), respectively. Again, these results advocate a role for localized corticosteroid injection in the management of SIJ dysfunction.

Platelet-rich plasma injection

Despite the aforementioned findings, the analgesic response of steroid injection is short term, frequently requiring reinjection and predisposing patients to steroid-related adverse effects. Injections of longer-acting agents, such as the biologic platelet-rich plasma (PRP), have been developed to attempt to overcome these shortcomings.

Singla et al. conducted a randomized control trial to compare ultrasound-guided intraarticular injection of 3 mL of leukocyte-free PRP with 0.5 mL of calcium chloride versus 1.5 mL of methylprednisolone (40 mg/mL) and 1.5 mL of 2% lidocaine with 0.5 mL of saline in 40 patients with moderate SIJ pain (VAS score >3) for at least 3 months. The diagnosis of SIJ pain was confirmed by the presence of three or more positive SIJ provocation tests (sacral thrust, iliac distraction, iliac compression, thigh thrust, Patrick’s test, and Gaenslen’s test) and imaging consistent with SIJ pathology (radiography, magnetic resonance imaging, or nuclear scan). Outcomes were measured by the VAS, Modified Oswestry Disability Index questionarie (MODQ), and Short Form 12 (SF-12; equally efficient abridgment of SF-36) Health Survey scores. Surveys were performed before the intervention and at 2, 4, 6, and 12 weeks after the intervention. Although the results showed significant reduction in pain intensity (measured by VAS) among all patients from baseline to each follow-up interval, there were no between-group differences in VAS scores at 2 and 4 weeks postinjection. In contrast, 90% of patients in the PRP group reported at least a 50% improvement in VAS at the 12-week interval compared with only 25% of patients in the steroid group at that time point ( P <.001). Pain intensity was also lower for the PRP group at 6 and 12 weeks than for the steroid group. Although MODQ and SF-12 scores progressively improved in the PRP group, they decreased in the steroid group at the 12-week follow-up despite an initial uptrend at 2 and 4 weeks. These results suggest PRP injections may have more prolonged analgesic effects and improved functional abilities compared with steroid injections.

Wallace et al. published similar findings regarding the efficacy of PRP injections at 6 months. In this study, 50 patients with more than 1 year of SIJ dysfunction and at least one previous SIJ steroid injection (though not within the last 3 months) underwent ultrasound-guided SIJ injection of 3 mL PRP. The diagnosis of SIJ dysfunction was determined by history and physical examination, imaging, and at least three positive provocative tests (Fortin finger test, Patrick’s test, posterior superior iliac spine distraction, Gaenslen’s test, pain mapping, thigh thrust test). The primary outcome scale was the ODI, and the secondary outcome scale was the NPRS score. Each measure was completed at baseline and at 1, 3, and 6 months postinjection. Results showed a significant improvement in ODI from baseline to 6 months after injection with the greatest reduction between 2 and 4 weeks. There was also a decrease in NPRS scores. By validating the results of the Singla et al. study with an even longer follow-up interval, this study established the sustainability of PRP injection in SIJ dysfunction.

A retrospective case series by Ko et al. investigated the efficacy of SIJ PRP injections in four patients with SIJ dysfunction; outcome measures included the Short-Form McGill Pain Questionnaire (SFM), NPRS, and ODI. Outcomes were recorded at 1 and 4 years posttreatment. Pooled data at 1-year postinjection showed a 93% reduction in mean SFM ( P <.0001), an 88% reduction in mean NPRS ( P <.001), and a 75% reduction in mean ODI ( P <.0001). The results remained significant at the 4-year follow-up, again substantiating the therapeutic efficacy and longevity of this intervention.

Lateral branch blocks

Although the previously mentioned studies advocate for SIJ injection, physicians have scrutinized this therapy to address concerns for injectate extravasation through defects in the joint capsule and inadequacy of coverage of the interosseous and dorsal sacroiliac ligaments. As an alternative interventional pain relief strategy, nerve blocks offered much promise. In a double-blind, randomized, placebo-controlled study, Dreyfuss et al. examined the efficacy of sacral lateral branch blocks in 20 healthy, asymptomatic volunteers. During the first session, participants underwent provocation testing through needle probing at the interosseous and dorsal sacroiliac ligaments, dorsal inferior SIJ entry, and capsular distension with contrast. At the second session (1 week later), participants were randomly assigned to receive 0.2 mL of bupivacaine 0.75% or 0.2 mL of normal saline injections at the L5 dorsal ramus and multisite, multidepth S1 to S3 lateral branches. Thirty minutes after the nerve block, provocation tests were repeated. The primary outcome measure in this study was the presence or absence of pain on repeat stimulation. Results showed that only 30% of participants in the active group experienced pain on repeat needle probing and joint entry; however, 80% of participants in the bupivacaine group reported pain with capsular distension. In contrast, 90% to 100% patients in the sham group reported pain with all three repeat provocative tests. These results suggest multisite, multidepth blocks may be 70% effective owing to insufficient coverage of the anterior component of the SIJ. Nonetheless, this study presented nerve blocks as a viable diagnostic and stratification tool in identifying patients with extraarticular SIJ pain who may benefit from lateral branch radiofrequency (RF) neurotomy.

Radiofrequency ablation

Radiofrequency ablation (RFA) is typically considered in patients who have failed the aforementioned therapies. This minimally invasive procedure targets sensory nerves surrounding the SIJ. Dutta et al. compared the efficacy of RF denervation against SIJ injection for the treatment of chronic SIJ pain in a randomized, single-blinded trial. Diagnosis of chronic SIJ dysfunction was defined as 3 months of low back tenderness over the SIJ or three or more positive provocative clinical test results (Gaenslen’s test, Patrick’s test, Gillet test, thigh thrust test, anterior superior iliac spine compression, and distraction test) and history of a positive response to local anesthetic SIJ injection (at least 80% pain reduction from baseline for a minimum of 5 hours postprocedure). Using these diagnostic criteria, 30 patients were randomized to receive intraarticular injectate (3 mL solution containing 2 mL of 0.5% bupivacaine and 1 mL of 40 mg/mL methylprednisolone) or pulsed RFA (average temperature, 38°–42°C for a duration 68 ± 12.2 minutes) at the L4 and L5 dorsal rami and S1 to S3 lateral branches. Successful outcomes were defined as a greater than 50% reduction in NPRS score, positive GPE, and at least a five-point reduction in ODI score. The primary outcome measure was NPRS scores, completed at baseline and 15, 30, 90, and 180 days after the procedure. Secondary outcome measures included the GPE and ODI; assessments were completed at baseline and at 90 and 180 days after the procedure. Positive GPE evaluation was indicated by positive response to the following three prompts: (1) “My pain has improved/worsened/stayed the same since my last visit,” (2) “The treatment I received improved/did not improve my ability to perform daily activities,” or (3) “I am satisfied/not satisfied with the treatment I received and would recommend it to others.” Results demonstrated similar NPRS scores at baseline between both groups. At 15 days after the procedure, the mean NPRS scores were more than 50% lower than baseline for both groups ( P = .4265). Relative to the 15-day follow-up, at 1 month after the procedure, scores remained stable in the steroid injection group from 3.333 to 3.333; in contrast, scores continued to downtrend in the RFA group from 3.200 to 2.933. At 3- and 6-month intervals, pain scores trended upward from the 15-day follow-up for the steroid group to 5.400 and stabilized for the RFA group at 3.200. Mean ODI scores ± SD at baseline were 14.6 ± 4.6 in the steroid group and 15.2 ± 4.3 in the RFA group; by the 6-month interval, the between-group differences were statistically significant with the steroid group scoring 13.1 ± 4.3 and the RFA group scoring 8.0 ± 3.7 ( P = .0017). Last, GPE responses were positive for 33% of the steroid group and 87% of the RFA group at the 3-month follow-up; at the 6-month follow-up, only 20% of the steroid group, compared to 87% of the RFA group, had positive GPE responses ( P <.05 at 6 months). With these findings, the authors of this randomized, single-blinded study provided ample evidence for the therapeutic efficacy of RFA in patients with SIJ dysfunction.

Another randomized controlled trial compared the efficacy of L4 to L5 primary dorsal rami and S1 to S3 lateral branch RFA against placebo denervation. Inclusion criteria included axial LBP for more than 6 months, pain over the SIJ refractory to conservative medical therapy, and pain relief of at least 75% for 6 hours after diagnostic SIJ injection. Twenty-eight participants were enrolled and subsequently randomized to cooled RFA or placebo. All patients were reexamined 1 month after the procedure by a physician blinded to interventions. In patients with a positive GPE and greater than 50% pain relief, follow-up examinations were repeated at 3 (intervention was unblinded during this evaluation) and 6 months; virtual appointments were completed every 2 months thereafter to determine duration of effect. In patients who did not have a positive GPE or less than 50% pain relief at the 1-month follow-up, the intervention was unblinded, and patients were offered alternative treatments—conventional, noncooled RFA for failed cooled RFA and crossover to cooled RFA for failed placebo. The primary outcome measure was the NPRS score; secondary outcome measures were the ODI, 20% reduction in opioid use or discontinuation of nonopioid analgesic, and GPE. Successful outcomes included at least 50% reduction in NPRS, positive GPE, and either a 10-point or greater reduction in ODI or a 4-point or greater reduction in ODI coupled with a reduction in analgesic pain medication. Results demonstrated significantly lower NPRS scores in the treatment group than the placebo group (mean ± SD, 2.4 ± 2.0 vs 6.3 ± 2.4, respectively; P <.001) at the 1-month follow-up. Within the RFA group, pain scores were reduced by 60%, 60%, and 57% at 1, 3, and 6 months from baseline, respectively. Eleven participants from the placebo group crossed over with similar reductions in NPRS scores after cooled RFA—44%, 67%, and 52% at 1, 3, and 6 months, respectively ( P <.001). With regard to secondary outcomes, the 1-month ODI scores were lower for the treatment arm than placebo (20.9 ± 10.9 vs 43.6 ± 14.0, respectively; P <.03). A within-group analysis for the RFA group similarly demonstrated lower ODI scores of 44%, 50%, and 39% at 1, 3, and 6 months, respectively, from baseline ( P <.001). In contrast, the mean ODI score of the placebo arm was unchanged at 1 month. The crossover placebo group’s ODI scores decreased by 28%, 59%, and 49% at 1, 3, and 6 months. Although the ODI scores did not differ significantly between the initial treatment group and the crossed over placebo group, the initial group did have lower ODI scores at 1 month (20.9 vs 34.3 ± 16.3; P <.03). Similarly, for GPE scores, the RFA group had higher scores at 1 month compared with the placebo group (93% vs 21%; P <.001). Last, the decrease in analgesic medication intake was greater in the RFA group than in the placebo at 1 month (77% vs 8%; P <.001), 3 months (82% vs 0%; P >.05), and 6 months (67% vs no data) with similar findings in the crossover placebo group. Regarding duration of analgesia, the treatment group had a mean duration of 5.8 months, and the placebo group reported a mean duration of 0.7 months. In summary, this study further supports the use of RFA in patients with SIJ pain.

Another study examined outcomes of SIJ pain after RFA. Diagnostic criteria for SIJ pain included at least one positive provocative test result (Gaenslen’s test, Patrick’s test, SIJ shear), reproduction of pain on insertion of needle into the SIJ, and at least 70% improvement in pain after injection of local anesthetics (outcomes measured VAS and pain relief score [PRS]). Patients reporting two or more flare-ups after local blocks, VAS score greater than 50, or pain interfering with ADLs were referred for RFA. VAS scores of 67 patients were recorded before treatment; within 2 hours of treatment; and at 1, 3, and 6 months after treatment to assess longevity of pain relief. Successful outcome was measured as PRS less than 5 or pain reduction of 50% or greater. If patients reported reflares during these intervals, RFA was repeated. Mean VAS scores before intervention were 70.8 ± 12.2 (mean ±SD); 2 hours after RFA, mean scores decreased to 18.8 ± 15.4 ( P <.001), and PRS was less than 5 for all participants. Thirty patients reported full recovery after initial treatment, with VAS less than 50 and no flares. Effectiveness rates, measured by percentage of PRS less than 5, were 100% immediately after treatment, 73% at 1 month, 46% at 3 months, and 43% at 6 months, with P <.01 between 1 and 3 months posttreatment. Thirty-seven patients required multiple treatments; however, of them, 34 reported lower pain scores after each treatment. Based on these results, the authors of this chapter suggested RFA may be considered as viable intervention before surgery.

Additionally, Tinnirello et al. performed a 1-year retrospective observational study comparing Simplicity III (conventional RF) versus SInergy (cooled RF), with both devices being specifically designed for SIJ denervation. Cooled RF has become popularized because of its novel water-cooled technology, exhibiting features of a lower tip temperature in combination with a larger spherical lesions size compared with conventional RF. The study was conducted using 43 patients with SIJ-derived pain refractory to conservative treatment for at least 6 months. The patients were divided between the Simplicity and SInergy groups (21 and 22 patients, respectively). The mean NPRS and ODI scores were determined for each study group to measure outcome for 1, 6, and 12 months postprocedure. The RF procedure was considered a “treatment success” if the patient reported a follow-up NRS score relative to the respective baseline score that was reduced by at least 50% or MCID in ODI scores between baseline and each of the follow-up time intervals with a decrease of 15% or more. Initially, the NRS scores of both groups were equivalent at approximately a score of 7. Throughout the study, the scores of the SInergy group were consistently lower than those of the Simplicity group. However, both groups showed similar patterns of initial dramatic reductions in mean NPRS scores at 1 month. The largest difference in pain reduction occurred at the 6- and 12-month interval scores, which were statistically significant ( P <.01) between the groups, favoring the SInergy group (NPRS score of 4.3 vs 2.7 at 6 months; 5.1 vs 3.5 at 12 months). Thus, 25% of the Simplicity participants who achieved treatment success at 1 month retained this status at 12 months. In contrast, 68% of SInergy participants who achieved treatment success at 1 month also maintained this success at 12 months. At 12 months, the Simplicity group reported NRS scores that had increased toward baseline values by an average of 50% versus the SInergy group. Twelve-month NRS scores increased relative toward baseline values by an average of 36%. The mean ODI scores of the SInergy group were consistently less than those of the Simplicity throughout the entirety of the 12-month period, with statistically significant ( P <.01) differences observed at 6 and 12 months. ODI scores illustrated treatment success by showcasing a MCID recognized as 15% or greater with 95% of the SInergy group noting “treatment success” at 1 month and remaining the same at the 6- and 12-month follow-ups. Although 90% of the Simplicity group had ODI score changes that met the MCID criteria at 1 month, there was a noticeable decline of participants who continued to meet the metric each follow-up time visit there afterward (90% at 1 month, 76% at 6 months, 62% at 12 months). This was further appreciated at the 6- and 12-month timeframe, when the SInergy group exceeding those of the Simplicity group by approximately 20% (76% vs 95% at 6 months) and 35% (62% vs 95% at 12 month), respectively. Overall, these data suggest that a greater proportion of patients in the SInergy group experienced superior pain and disability outcomes than those of the Simplicity group at each follow-up, especially at 6 and 12 months. It appears that both conventional RF and cooled RF are effective at treating SIJ pain in the short term, but cooled RF produces significantly longer pain relief that persists. It has been suggested that cooled RF technology allows an interventionalist to create more accurate lesioning of the target nerves because of its larger lesion size, which could explain the longer pain relief.

Peripheral nerve stimulation

Traditionally, patients with SIJ pain unresponsive to conventional progression of treatments (i.e., physiotherapy, antiinflammatory medication, repetitive intraarticular SIJ with local anesthetics and steroids or biologics, neurotomy of the L5–S3 dorsal rami) was were for SIJ arthrodesis or fusion. However, recent research into peripheral nerve stimulation (PNS) presents new opportunities for interventional pain relief. Guentchev et al. extrapolated PNS to the SIJ. Twelve patients with medically refractory SIJ pain were recruited for subcutaneous SIJ neurostimulator implantation. Inclusion criteria included a positive provocative test result (Gillette test, Gaenslen’s test, Patrick’s test) and a positive SIJ diagnostic test result followed by a steroidal SIJ injection 2 weeks later. Stimulators were implanted after pain recurrence. Outcomes measures included the VAS, ODI, and International Patient Satisfaction Index (IPSI), which were performed before stimulation and at 1 to 2 weeks, 1 to 2 months, 6 months, and 12 months after stimulation. Positive outcome was defined as ISPI score less than or equal to 2. Results demonstrated mean VAS decreased from 9 at baseline to 2.1 at the 2-week interval, 3.8 at the 6-month interval ( P <.0001), and 1.7 at the 12-month interval ( P <.0001). ODI decreased from 57% at baseline to 32% at the 2-week interval, 34% at the 6-month interval ( P = .0006), and 21% at the 12-month interval ( P <.0005). The IPSI was 1.1 at the 2-week interval, 1.9 at the 6-month interval, and 1.3 at the 12-month interval. The results from this study fostered further investigations into nonsurgical approaches to refractory SIJ pain.

Another study compared percutaneous PNS of medial branch nerves in patients with chronic axial back pain. This was a prospective, multicenter trial that recruited 15 patients with recurrent pain after RFA. Specific inclusion criteria included presence of nonradiating, lumbar LBP for at least 12 weeks, stable analgesic medication use for at least 4 weeks, and baseline pain intensity of at least greater than or equal to 4 on the Brief Pain Inventory Short Form-question 5 (BPI-5). Patients underwent ultrasound- and/or fluoroscopy-guided implantation of percutaneous peripheral nerve stimulators targeting the medial branch nerves overlying the lamina medial and inferior to the facet joint. After 60 days of stimulation, leads were removed, and patients were followed for 5 months. Primary outcomes were daily pain levels and pain medication intake as recorded by patients in weekly diaries; secondary outcomes included the ODI, Brief Pain Inventory-9 (BPI-9), and patient global impression of change. At baseline, average pain intensity was 6.3 (SD, 1.0; BPI-5, scale 0–10). This score decreased to 2.4 ± 1.6 at 2 months ( P <.0001) and 3.1 ± 1.9 at 5 months ( P <.0001). Similarly, ODI scores were 43.1 ± 12.7 at baseline, 21.8 ± 13.9 at 2 months ( P = 0.0002), and 26.1 ± 13.2 at 5 months ( P = .003). BPI-9 scores were 6.2 ± 1.8 at baseline, 2.4 ± 2.1 at 2 months ( P <.0001), and 3.2 ± 2.7 at 5 months ( P = .0016). This report highlights the sustainability and effectiveness of PNS for the treatment of patients with SIJ pain.

Arthrodesis

When SIJ pain is refractory to minimally invasive interventions, most physicians recommend SIJ arthrodesis. Buchowski et al. implied arthrodesis improves postoperative function through their case series. Patients were considered for the arthrodesis only if they had recurrence of SIJ pain after intraarticular SIJ injection and failed all other nonoperative treatments. In total, 20 patients underwent arthrodesis via modified Smith-Petersen or posterior approach. Efficacy of the intervention was measured by performance on the SF-36 and American Academy of Orthopedic Surgeons (AAOS) Modems Instrument. Of the 20 patients, 17 had solid fusion. Fifteen completed the preoperative and postoperative SF-36 (unspecified interval between procedure and completion of post-procedure evaluations), with significant improvement ( P ≤.05) in physical functioning, role physical, bodily pain, vitality, social functioning, role emotional, and neurogenic and pain indices. Although not statistically significant, improvement was also noted in general and mental health ( P <.4706 and P <.0604, respectively). On the AAOS Modems Instrument, patients expressed improvement in the Neurogenic Symptoms Index ( P <.0194), Pain/Disability Index ( P <.0007), and Satisfaction with Symptoms Index ( P <.0065). These results advocate for arthrodesis in patients with SIJ pain unresponsive to conservative measures.

A systematic review reinforcing these findings compared the effectiveness of SIJ fusion. Inclusion criteria were original, peer-reviewed, prospective or retrospective studies with more than two participants. Pertinent exclusion criteria were follow-up less than 1 year and nonsurgical intervention. The review analyzed 16 studies with a total of 430 patients: 131 open procedures and 299 minimally invasive surgical procedures (MIS). Outcome assessment tools were varied among studies; however, many included VAS, SF-36, ODI, NPRS, Majeed scoring system, satisfactory assessment questionnaire, and patient verbal satisfaction. The average durations of follow-up were 60 months for open surgery and 21 months for MIS. Among participants who underwent open surgery, success rates ranged from 20% to 90%; excellent satisfaction ranged from 18% to 100% with a mean of 54% and poor satisfaction, determined by patients indicating they would have rather not had surgery, ranged from 0% to 47%, with a mean of 32%. Among the participants who underwent MIS, excellent satisfaction ranged from 56% to 100%, with a mean of 84%, thus supporting the therapeutic value of this procedure.