What is the differential diagnosis and treatment for a 3-month postpartum woman with coccyx pain that started after delivery 2 years ago, improved, then worsened after a recent vaginal delivery with epidural (epidural anesthesia)?

Postpartum Coccydynia: Differential Diagnosis and Management

Direct Answer

This patient has postpartum coccydynia, most likely caused by coccygeal luxation or fracture from her vaginal deliveries, particularly given the temporal relationship to childbirth and the pattern of initial improvement followed by recurrence after the second delivery. 1

Differential Diagnosis

Primary Considerations (Coccygeal Origin)

Coccygeal luxation is the most likely diagnosis, occurring in 43.9% of postpartum coccydynia cases compared to only 17.0% of non-obstetric coccydynia. 1 This condition:

• Appears immediately when adopting sitting position after delivery 1
• Is strongly associated with instrumental deliveries (forceps in 50.8%, vacuum in 7.0%) or difficult spontaneous deliveries (12.3%) 1
• Shows abnormal coccygeal mobility in approximately 70% of all coccydynia cases 2

Coccygeal fracture occurs in 5.3% of postpartum coccydynia cases and represents the second most characteristic lesion. 1

Abnormal coccygeal mobility (hypermobility, anterior/posterior subluxation) can result from chronic overload and is demonstrable on dynamic radiographs. 2

Sacrococcygeal or intercoccygeal disc degeneration may develop from repetitive trauma. 2

Coccygeal spicule (bony excrescence) can develop and cause persistent symptoms. 2

Secondary Considerations (Non-Coccygeal Origin)

Pilonidal cyst or perianal abscess - though she denies rectal symptoms, these should be excluded on examination. 2

Lumbosacral spine disorders, sacroiliac joint dysfunction, or piriformis muscle syndrome - though less likely given the specific coccygeal location and timing. 2

Idiopathic coccydynia accounts for 30% of cases when no specific cause is identified. 2

Diagnostic Approach

Clinical Examination

Perform systematic coccygeal evaluation including: 2

• External palpation of the coccyx for tenderness and mobility
• Intrarectal examination to assess coccygeal mobility and reproduce symptoms 3, 2
• Pain provocation testing during rectal examination 3
• Assessment of sitting tolerance and pain with sit-to-stand transitions 3

Imaging Studies

Dynamic radiography is the initial imaging of choice, consisting of lateral X-rays of the coccyx in both standing and sitting positions to assess abnormal mobility. 2, 1 This reveals luxation or subluxation in the majority of postpartum cases. 1

If plain radiographs are inconclusive but clinical suspicion remains high, obtain MRI or CT imaging, which can reveal coccygeal pathology not visible on plain films. 4 MRI is particularly useful for evaluating soft tissue structures and disc degeneration. 4

Diagnostic injection of local anesthetic into the sacrococcygeal disc, first intercoccygeal disc, or Walther's ganglion can confirm coccygeal origin of pain. 2

Treatment Algorithm

Conservative Management (First-Line for All Patients)

Initial conservative therapy should include: 2, 5

• Coccyx cushion (donut cushion) for offloading during sitting 5
• NSAIDs for pain control 5
• Physical therapy including manual therapy (massage and stretching of levator ani muscle, mobilization of the coccyx) 2
• Activity modification to avoid prolonged sitting 2

If symptoms persist after 4-6 weeks, proceed to: 2

• Corticosteroid injection into painful structures (sacrococcygeal joint, intercoccygeal disc) 2
• Consider radiofrequency ablation of coccygeal discs and Walther's ganglion for refractory cases 2

Surgical Management (For Refractory Cases)

Coccygectomy is indicated when conservative measures fail, particularly in patients with: 2, 5

• Documented abnormal coccygeal mobility on dynamic radiographs 2
• Coccygeal spicules 2
• Persistent symptoms despite 6-12 months of comprehensive conservative therapy 5

The paramedian approach (0.5-1.5 cm lateral to midline) is preferred over traditional midline incision because it: 5

• Distances the surgical site from the anus
• Diminishes the crevice effect of the gluteal cleft
• Increases dermal thickness for improved closure
• Results in lower infection rates (12.1% with paramedian vs. historically higher rates with midline) 5

Expected surgical outcomes: 5

• VAS pain reduction from 7.5 to 2.3 (p<0.001) 5
• Oswestry Disability Index improvement from 30.1 to 9.6 (p<0.001) 5
• 86.7% of patients report good or excellent results 5
• Maximum improvement typically occurs >1 year postoperatively 5

Important Clinical Pearls

Risk factors for postpartum coccygeal luxation include: 1

• Body mass index >27 1
• ≥2 vaginal deliveries 1
• Instrumental delivery (forceps or vacuum) 1

The epidural anesthesia itself is not a causative factor - the mechanism is direct trauma to the coccyx during delivery, not the anesthetic technique. 1

Rectal examination is essential and improves detection of coccygeal pathology; it should be performed in all suspected cases despite patient reluctance. 2

Conservative therapy achieves satisfactory results in the majority of patients, so surgical intervention should be reserved for truly refractory cases after exhausting non-operative options. 2